Samsung Air Conditioner Error Code P402

P402 means the condensate temperature sensor on the compressor has detected a temperature at or above 67°C, indicating the outdoor unit is overheating. The system is designed to tolerate this condition up to five times before initiating a full shutdown on the sixth detection. The code is a thermal protection response intended to prevent compressor damage. In most cases the cause is restricted airflow or a dirty condenser coil at the outdoor unit.

No. P402 indicates that the compressor is being exposed to excessive heat, and continuing to operate the system under these conditions risks permanent compressor damage. The unit shuts itself down on the sixth detection specifically to prevent this outcome. The underlying cause should be identified and corrected before restarting the system.

Repair costs depend heavily on the root cause. A professional coil cleaning service typically ranges from around $75 to $200. Condenser fan motor replacement generally falls between $150 and $400 including parts and labor. Refrigerant diagnosis and recharge can range from $150 to $500 or more depending on refrigerant type and the amount required. Sensor replacement is usually one of the lower-cost repairs, often in the $100 to $250 range.

Some causes of P402 can be addressed without a technician, including clearing debris from around the outdoor unit, removing nearby obstructions, and rinsing a dirty condenser coil. If these steps do not resolve the issue, problems such as a refrigerant charge imbalance, a failing fan motor, or a defective sensor require professional tools and certification to diagnose and repair safely.

A power cycle or reset may clear the active fault and allow the unit to restart, but it will not resolve the underlying cause. If the airflow restriction, coil fouling, or other contributing factor is still present, the condensate temperature will rise again and the system will eventually shut down again. Clearing the code without fixing the root cause risks accelerating compressor wear.